Object: bone deformities in growing patients with osteogenesis imperfecta. Aim: to improve the results of surgical correction of long bones deformities in children with osteogenesis imperfecta by inventing a new intramedullary telescopic fixator (nail) characterizing by axial, angular and rotationally stability and proving an effectiveness of this new fixator. Methods: clinical, biomechanical, radiological, radiometric, dual energy x-ray densitometry, mathematical finite element simulation, statistical. Features of the strained-deformed state of the system "fragments of the bone – intramedullary fixator" were studied on the experimental biomechanical models for the first time. It allowed to prove the effectiveness of intramedullary telescopic fixators comparing to non-telescopic and extramedullary fixators, under the influence of different forces - axial, angular and rotational. For the first time, based on X-ray studies, it was proved that, in the postoperative period, the elongation values of the invented intramedullary telescopic fixator correspond to bone growth values in the patients with osteogenesis imperfecta. It is proved that usage of intramedullary telescopic fixators is a modern and effective method to treat long limb bones deformities in children with osteogenesis imperfecta and does not require long-term usage of additional external devices that improves treatment results. An intramedullary telescopic fixator (patent number 88254, Ukraine) for the surgical treatment of combined long bones deformities in children with osteogenesis imperfecta was invented. It allows a bone to grow in length, helps to prevent deformities recurrences, reduces the risk of refractures, and improves the patients’ life quality in general. The technique of the surgical correction of long bones combined deformities in patients with osteogenesis imperfecta was improved, that gave an opportunity to reduce the duration of surgical intervention, begin rehabilitation earlier and to perform the self-service for patients earlier. X-ray and X-ray based measuring systems for assessing the dynamics of the limb segments growth and the elongation of the intramedullary telescopic fixator that promotes effective results control of the surgical treatment over time in children with long bones deformities on the background of osteogenesis imperfecta. Usage of the developed algorithm for examination and staged treatment of patients with osteogenesis imperfecta allows to reduce mistakes occurrence during the stages of treatment, preparation for surgical interventions and further complications, thus, to improve the treatment quality. The research results were introduced into the clinical practice of SI "Sytenko Institute of Spine and Joint Pathology National Academy of Medical Sciences of Ukraine", MNE of the Kharkiv Regional Council "Regional Clinical Trauma Hospital", MNE "Lviv Regional Children's Clinical Hospital "OKHMATDET". Тraumatology and Orthopaedics.
